Possible adverse effects of exposure to anticonvulsants on neurological development via breastfeeding have so far only been directly compared by two previous studies, in which mainly older drugs were used.3
The ongoing, prospective observational study MONEAD (Maternal Outcomes and Neurodevelopmental Effects of Antiepileptic Drugs) examined 258 children whose mothers had taken one (79%) or more (21%) anticonvulsants during the third trimester. The most common drugs were lamotrigine (35%), levetiracetam (28%) or both (10%), followed by carbamazepine, zonisamide, oxcarbazepine and topiramate.
195 of the children were breastfed (75%), 63 were not. At the age of three, there was no significant influence of breastfeeding or non-breastfeeding on verbal development or cognitive abilities. The children's developmental status also did not differ between breastfeeding mothers who took several medications and those who took only one medication.
Surveying at age 3 provides a fairly reliable indicator of the status of neurological development. "At 3 years old, their brains are further developed and they are more willing to cooperate with you, allowing you to test more things," Meador says. "I think age 6 is probably best, but age 3 is pretty good." This, too, will be left to prove as the MONEAD study will follow up children until they are 6 years of age.1
One concern has always been the fact that most antiepileptic drugs do pass into breast milk (ESM, LEV, LTG, TPM, GBP, OXC, PRM, CNS). However, there are two things to consider: the higher the plasma protein binding, the lower the passing into milk.4 Another possible reason why we see no adverse effect on the development was described by Meador and team in a previous paper: the concentration of anticonvulsants in the breastfed infants' blood is lower – often considerably lower – than the levels in the mother's blood. This may be attributed to the higher metabolic rate of infants.
Still, there are of course limitations:
Further studies are needed for many of the newer agents.
Phenobarbital (Luminal®) and primidone (Liskantin®) are not recommended because of a potentially sedating effect. Finally, precautionary measures for breastfeeding may need to be taken if the mother continues to suffer seizures.
An epilepsy specialist independent of the study, Prof. Abrar Omar Al-Faraj of Boston University, sees many unanswered questions in the lactation counselling of epileptic mothers on polytherapy (two or more anticonvulsants). "There is concern of a cumulative effect of the drugs on the breastfed infant, which could lead to short- or long-term side effects [...]. I think more research is needed in this area."1
Last access to these links: 23 April 2022